The Experts below are selected from a list of 360 Experts worldwide ranked by ideXlab platform
Yanxia Zhao - One of the best experts on this subject based on the ideXlab platform.
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coagulation performance evaluation of sodium alginate used as coagulant aid with aluminum sulfate iron chloride and titanium tetrachloride
Desalination, 2012Co-Authors: Yanxia Zhao, Yang Wang, Ho Kyong ShonAbstract:Abstract Coagulation–flocculation was applied to humic acid–kaolin Synthetic Water samples, using sodium alginate (SA) as a coagulant aid with primary coagulants used: aluminum sulfate (Al2(SO4)3), iron chloride (FeCl3) and titanium tetrachloride (TiCl4). The corresponding dual-coagulants were dented as Al2(SO4)3–SA, FeCl3–SA and TiCl4–SA by dosing SA 30 s after primary coagulants addition. Coagulation performance was investigated in terms of turbidity reduction and dissolved organic carbon (DOC) removal and the flocs were characterized in terms of size, growth rate, strength, recoverability and structure through on‐line monitoring of the coagulation process using Mastersizer 2000. The results showed that dual-coagulants could remove HA effectively with appropriate SA doses. Primary coagulants plus SA exhibited an apparent improvement in both floc growth rate and floc size. Besides, floc recoverability was significantly increased. It was suspected that SA addition may have a positive effect on the solid/liquid separation process. However, dual-coagulants gave the flocs with more open structure.
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the disinfection by products precursors removal efficiency and the subsequent effects on chlorine decay for humic acid Synthetic Water treated by coagulation process and coagulation ultrafiltration process
Chemical Engineering Journal, 2012Co-Authors: Yan Wang, Qinyan Yue, Baoyu Gao, Qian Wang, Yanxia ZhaoAbstract:Abstract The disinfection by-products (DBPs) precursors removal efficiency and the subsequent effects on chlorine decay of coagulation–ultrafiltration process were studied in a laboratory in comparison with coagulation process. And the relation between flocs properties and the performance of coagulation–ultrafiltration process was investigated by the experiments of flocs size, fractal dimension and the surface charge. The removal efficiency of coagulation–ultrafiltration process showed that turbidity and UV254 could be removed efficiently regardless of polyferric chloride (PFC) dosage and solution pH. Even when dosage was 3 mg L−1, the turbidity and UV254 removal efficiencies were higher than 90% in coagulation–ultrafiltration process. The chlorine decay showed that under various technological conditions, the difference between chlorine decay curves obtained by coagulation–ultrafiltration process was less than that obtained by coagulation process. According to the analysis by AQUASIM software, the concentration of fast reducing agents (FRA) in coagulation–ultrafiltration process is lower than that in coagulation process, but the concentration of Slow Reducing Agents (SRA) in coagulation–ultrafiltration process was higher than in coagulation process except dosage = 18 mg L−1. Comparing the flocs properties to the performance of coagulation–ultrafiltration process, it can be found that when flocs size was small ( 200 μm), the HA removal efficiency was influenced mainly by flocs structure. The more compact the flocs, the higher the HA removal efficiency.
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the impacts of coagulant aid polydimethyldiallylammonium chloride on coagulation performances and floc characteristics in humic acid kaolin Synthetic Water treatment with titanium tetrachloride
Chemical Engineering Journal, 2011Co-Authors: Yanxia Zhao, Ho Kyong Shon, Baoyu Gao, Qinyan Yue, Hongyan Rong, Jin Hyeok Kim, Yang WangAbstract:Abstract Coagulation of humic acid–kaolin Synthetic Water was conducted with Titanium tetrachloride (TiCl4) and/or polydimethyldiallylammonium chloride (PD) to assess the effect of coagulant aid PD on coagulation behavior and floc characteristics. Coagulation behavior was investigated in terms of the reduction of turbidity and the removal of natural organic matter (NOM). The results show that the humic acid (HA) removal increased with the addition of PD depending on the doses of it and TiCl4, and the HA removal was more enhanced by PD at low TiCl4 doses than at higher ones. In addition, PD–TiCl4 (PD dosed firstly, followed by TiCl4 addition) gave better turbidity and HA removal than TiCl4–PD (TiCl4 dosed firstly, followed by PD addition) in this investigation. The growth, breakage, regrowth and fractal nature of flocs was investigated by use of Mastersizer 2000. TiCl4 plus cationic polymer PD exhibited an apparent improvement on floc size and floc grow rate, and they were both in the following order: PD–TiCl4 > TiCl4–PD > TiCl4. Compared with TiCl4, the dual-coagulants significantly improved the floc recoverability. Besides, the dual-coagulants gave more compact floc structure than TiCl4 coagulant at each coagulant dose under investigation and the values of fractal dimension (Df) were in the order of TiCl4–PD > PD–TiCl4 > TiCl4.
Yan Wang - One of the best experts on this subject based on the ideXlab platform.
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cuo nanoparticle humic acid cuonp ha composite contaminant removal by coagulation ultrafiltration process the application of sodium alginate as coagulant aid
Desalination, 2015Co-Authors: Yan Wang, Han Yan, Nan Xue, Yongbao Chu, Yangyang Sun, Qi HanAbstract:Abstract In order to remove CuO nanoparticle–humic acid composite contaminant (CuONP–HA) and reduce the membrane fouling in coagulation/ultrafiltraion process, sodium alginate (SA) was used as a coagulant aid of polyaluminum chloride (PAC) to pre-treat CuONP–HA in Synthetic Water. The effect of SA on floc properties and membrane fouling was investigated by a laser diffraction instrument and ultrafiltration fouling model. The results showed that SA, as coagulant aid, could improve the removal efficiency of CuONP–HA by coagulation/ultrafiltration process. CuONP was completely removed, and the removal efficiency of HA was over 80% at PAC dosage = 3.0 mg/L and SA dosage ≥ 0.2 mg/L. Besides, PAC with SA (PAC + SA) could form larger flocs with better recoverability than PAC alone. The average size of CuONP–HA flocs formed by PAC + SA exceeded 1000 um which was about 66% larger than flocs formed by PAC, and the small CuONP–HA aggregation also increased to about 280 um. Moreover, membrane fouling was effectively reduced by pre-treating of SA, and membrane fouling index (MFI) was decreased with the dosage of SA increasing.
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the disinfection by products precursors removal efficiency and the subsequent effects on chlorine decay for humic acid Synthetic Water treated by coagulation process and coagulation ultrafiltration process
Chemical Engineering Journal, 2012Co-Authors: Yan Wang, Qinyan Yue, Baoyu Gao, Qian Wang, Yanxia ZhaoAbstract:Abstract The disinfection by-products (DBPs) precursors removal efficiency and the subsequent effects on chlorine decay of coagulation–ultrafiltration process were studied in a laboratory in comparison with coagulation process. And the relation between flocs properties and the performance of coagulation–ultrafiltration process was investigated by the experiments of flocs size, fractal dimension and the surface charge. The removal efficiency of coagulation–ultrafiltration process showed that turbidity and UV254 could be removed efficiently regardless of polyferric chloride (PFC) dosage and solution pH. Even when dosage was 3 mg L−1, the turbidity and UV254 removal efficiencies were higher than 90% in coagulation–ultrafiltration process. The chlorine decay showed that under various technological conditions, the difference between chlorine decay curves obtained by coagulation–ultrafiltration process was less than that obtained by coagulation process. According to the analysis by AQUASIM software, the concentration of fast reducing agents (FRA) in coagulation–ultrafiltration process is lower than that in coagulation process, but the concentration of Slow Reducing Agents (SRA) in coagulation–ultrafiltration process was higher than in coagulation process except dosage = 18 mg L−1. Comparing the flocs properties to the performance of coagulation–ultrafiltration process, it can be found that when flocs size was small ( 200 μm), the HA removal efficiency was influenced mainly by flocs structure. The more compact the flocs, the higher the HA removal efficiency.
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effect of ph on the coagulation performance of al based coagulants and residual aluminum speciation during the treatment of humic acid kaolin Synthetic Water
Journal of Hazardous Materials, 2010Co-Authors: Zhong Lian Yang, Yan WangAbstract:Abstract The fractionation and measurement of residual aluminum was conducted during the treatment of humic (HA)–kaolin Synthetic Water with Al 2 (SO 4 ) 3 , AlCl 3 and polyaluminum chloride (PAC) in order to investigate the effect of pH on the coagulation performance as well as residual aluminum speciation. Experimental results suggested that turbidity removal performance varied according to the following order: AlCl 3 > PAC > Al 2 (SO 4 ) 3 . HA removal performance of PAC was better than that of AlCl 3 under acidic condition. The optimum pH range for AlCl 3 and Al 2 (SO 4 ) 3 was between 6.0 and 7.0 while PAC showed stable HA and UV 254 removal capacity with broader pH variation (5.0–8.0). For the three coagulants, majority of residual aluminum existed in the form of total dissolved Al (60–80%), which existed mostly in oligomers or complexes formed between Al and natural organic matter or polymeric colloidal materials. PAC exhibited the least concentration for each kind of residual aluminum species as well as their percentage in total residual aluminum, followed by AlCl 3 and Al 2 (SO 4 ) 3 (in increasing order). Moreover, PAC could effectively reduce the concentration of dissolved monomeric Al and its residual aluminum ratio was the least among the three coagulants and varied little at an initial pH between 7.0 and 9.0.
Baoyu Gao - One of the best experts on this subject based on the ideXlab platform.
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coagulation performance and floc characteristics of polytitanium tetrachloride ptc compared with titanium tetrachloride ticl4 and iron salts in humic acid kaolin Synthetic Water treatment
Separation and Purification Technology, 2015Co-Authors: Laura Chekli, J Galloux, Yi Zhao, Baoyu Gao, Ho Kyong ShonAbstract:Abstract Polymeric metal coagulants are increasingly used to improve the coagulation/flocculation process efficiency, yet the research on the development of titanium and particularly polytitanium salts remains very limited. In this study, the performance of recently developed polytitanium tetrachloride (PTC) coagulant was compared with both titanium tetrachloride (TiCl 4 ) and a commonly used coagulant, ferric chloride (FeCl 3 ) in terms of Water quality parameters and floc properties. Compared with FeCl 3 coagulant, titanium-based coagulants had broader region of good flocculation in terms of pH and coagulant dose. Further, they achieved higher removal of UV 254 and turbidity but lower dissolved organic carbon (DOC) removal. Charge neutralisation, physical entrapment of colloids within coagulant precipitates and adsorption were found to be the main coagulation mechanisms for TiCl 4 while sweep coagulation and adsorption were found to play a more important role for both FeCl 3 and PTC. The aggregated flocs formed by PTC flocculation had the largest floc size of around 836 μm with the highest floc growth rate. A little distinction of the floc strength factor was found among the coagulants tested (i.e. 44.8%, 44.2% and 38.9% for FeCl 3 , TiCl 4 and PTC respectively) while TiCl 4 coagulant yielded the flocs with the highest floc recovery factor. This study indicates that Ti-based coagulants are effective and promising coagulants for Water purification. Besides, the resulted flocculated sludge can be recycled and produce functional TiO 2 photocatalyst which is a significant advantage over conventional coagulants.
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the disinfection by products precursors removal efficiency and the subsequent effects on chlorine decay for humic acid Synthetic Water treated by coagulation process and coagulation ultrafiltration process
Chemical Engineering Journal, 2012Co-Authors: Yan Wang, Qinyan Yue, Baoyu Gao, Qian Wang, Yanxia ZhaoAbstract:Abstract The disinfection by-products (DBPs) precursors removal efficiency and the subsequent effects on chlorine decay of coagulation–ultrafiltration process were studied in a laboratory in comparison with coagulation process. And the relation between flocs properties and the performance of coagulation–ultrafiltration process was investigated by the experiments of flocs size, fractal dimension and the surface charge. The removal efficiency of coagulation–ultrafiltration process showed that turbidity and UV254 could be removed efficiently regardless of polyferric chloride (PFC) dosage and solution pH. Even when dosage was 3 mg L−1, the turbidity and UV254 removal efficiencies were higher than 90% in coagulation–ultrafiltration process. The chlorine decay showed that under various technological conditions, the difference between chlorine decay curves obtained by coagulation–ultrafiltration process was less than that obtained by coagulation process. According to the analysis by AQUASIM software, the concentration of fast reducing agents (FRA) in coagulation–ultrafiltration process is lower than that in coagulation process, but the concentration of Slow Reducing Agents (SRA) in coagulation–ultrafiltration process was higher than in coagulation process except dosage = 18 mg L−1. Comparing the flocs properties to the performance of coagulation–ultrafiltration process, it can be found that when flocs size was small ( 200 μm), the HA removal efficiency was influenced mainly by flocs structure. The more compact the flocs, the higher the HA removal efficiency.
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synthesis and floc properties of polymeric ferric aluminum chloride polydimethyl diallylammonium chloride coagulant in coagulating humic acid kaolin Synthetic Water
Chemical Engineering Journal, 2012Co-Authors: Baoyu Gao, Qinyan Yue, Cuizhen Sun, Baichuan Cao, Zhibin ZhangAbstract:Abstract In this paper, new composite coagulants, polymeric ferric aluminum–polydimethyl diallylammonium chloride, were synthesized by combing inorganic coagulant polymeric ferric aluminum chloride (PFAC) with organic coagulant polymer polydimethyl diallylammonium chloride (PDMDAAC) under different molecular weight ratio (ferrum and aluminum to PDMDAAC, Wr = 20, 10 and 4) and the same basicity. Furthermore, flocculating mechanisms and performance of these new composite coagulants were investigated in treating humic–kaolin Synthetic wasteWater. The growth, breakage, and regrowth of flocs during coagulation using composite coagulants were measured under optimal dosage and neutral conditions by a laser diffraction instrument. The coagulation results indicated that the new composite coagulants exhibited better coagulation performance than PFAC for removing turbidity and dissolved organic matter. For the composite coagulants, the predominant coagulation mechanisms were bridge formation and charge neutralisation. The composite coagulants with different molecular weight ratio gave different steady-state floc size, strength and reflocculation ability. Both the floc size and reflocculation ability were in the same order of Wr = 4 > Wr = 10 > Wr = 20 > PFAC, while the order of floc strength was in the order of Wr = 20 > Wr = 10 > Wr = 4 > PFAC.
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the impacts of coagulant aid polydimethyldiallylammonium chloride on coagulation performances and floc characteristics in humic acid kaolin Synthetic Water treatment with titanium tetrachloride
Chemical Engineering Journal, 2011Co-Authors: Yanxia Zhao, Ho Kyong Shon, Baoyu Gao, Qinyan Yue, Hongyan Rong, Jin Hyeok Kim, Yang WangAbstract:Abstract Coagulation of humic acid–kaolin Synthetic Water was conducted with Titanium tetrachloride (TiCl4) and/or polydimethyldiallylammonium chloride (PD) to assess the effect of coagulant aid PD on coagulation behavior and floc characteristics. Coagulation behavior was investigated in terms of the reduction of turbidity and the removal of natural organic matter (NOM). The results show that the humic acid (HA) removal increased with the addition of PD depending on the doses of it and TiCl4, and the HA removal was more enhanced by PD at low TiCl4 doses than at higher ones. In addition, PD–TiCl4 (PD dosed firstly, followed by TiCl4 addition) gave better turbidity and HA removal than TiCl4–PD (TiCl4 dosed firstly, followed by PD addition) in this investigation. The growth, breakage, regrowth and fractal nature of flocs was investigated by use of Mastersizer 2000. TiCl4 plus cationic polymer PD exhibited an apparent improvement on floc size and floc grow rate, and they were both in the following order: PD–TiCl4 > TiCl4–PD > TiCl4. Compared with TiCl4, the dual-coagulants significantly improved the floc recoverability. Besides, the dual-coagulants gave more compact floc structure than TiCl4 coagulant at each coagulant dose under investigation and the values of fractal dimension (Df) were in the order of TiCl4–PD > PD–TiCl4 > TiCl4.
Ho Kyong Shon - One of the best experts on this subject based on the ideXlab platform.
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coagulation performance and floc characteristics of polytitanium tetrachloride ptc compared with titanium tetrachloride ticl4 and iron salts in humic acid kaolin Synthetic Water treatment
Separation and Purification Technology, 2015Co-Authors: Laura Chekli, J Galloux, Yi Zhao, Baoyu Gao, Ho Kyong ShonAbstract:Abstract Polymeric metal coagulants are increasingly used to improve the coagulation/flocculation process efficiency, yet the research on the development of titanium and particularly polytitanium salts remains very limited. In this study, the performance of recently developed polytitanium tetrachloride (PTC) coagulant was compared with both titanium tetrachloride (TiCl 4 ) and a commonly used coagulant, ferric chloride (FeCl 3 ) in terms of Water quality parameters and floc properties. Compared with FeCl 3 coagulant, titanium-based coagulants had broader region of good flocculation in terms of pH and coagulant dose. Further, they achieved higher removal of UV 254 and turbidity but lower dissolved organic carbon (DOC) removal. Charge neutralisation, physical entrapment of colloids within coagulant precipitates and adsorption were found to be the main coagulation mechanisms for TiCl 4 while sweep coagulation and adsorption were found to play a more important role for both FeCl 3 and PTC. The aggregated flocs formed by PTC flocculation had the largest floc size of around 836 μm with the highest floc growth rate. A little distinction of the floc strength factor was found among the coagulants tested (i.e. 44.8%, 44.2% and 38.9% for FeCl 3 , TiCl 4 and PTC respectively) while TiCl 4 coagulant yielded the flocs with the highest floc recovery factor. This study indicates that Ti-based coagulants are effective and promising coagulants for Water purification. Besides, the resulted flocculated sludge can be recycled and produce functional TiO 2 photocatalyst which is a significant advantage over conventional coagulants.
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coagulation performance evaluation of sodium alginate used as coagulant aid with aluminum sulfate iron chloride and titanium tetrachloride
Desalination, 2012Co-Authors: Yanxia Zhao, Yang Wang, Ho Kyong ShonAbstract:Abstract Coagulation–flocculation was applied to humic acid–kaolin Synthetic Water samples, using sodium alginate (SA) as a coagulant aid with primary coagulants used: aluminum sulfate (Al2(SO4)3), iron chloride (FeCl3) and titanium tetrachloride (TiCl4). The corresponding dual-coagulants were dented as Al2(SO4)3–SA, FeCl3–SA and TiCl4–SA by dosing SA 30 s after primary coagulants addition. Coagulation performance was investigated in terms of turbidity reduction and dissolved organic carbon (DOC) removal and the flocs were characterized in terms of size, growth rate, strength, recoverability and structure through on‐line monitoring of the coagulation process using Mastersizer 2000. The results showed that dual-coagulants could remove HA effectively with appropriate SA doses. Primary coagulants plus SA exhibited an apparent improvement in both floc growth rate and floc size. Besides, floc recoverability was significantly increased. It was suspected that SA addition may have a positive effect on the solid/liquid separation process. However, dual-coagulants gave the flocs with more open structure.
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the impacts of coagulant aid polydimethyldiallylammonium chloride on coagulation performances and floc characteristics in humic acid kaolin Synthetic Water treatment with titanium tetrachloride
Chemical Engineering Journal, 2011Co-Authors: Yanxia Zhao, Ho Kyong Shon, Baoyu Gao, Qinyan Yue, Hongyan Rong, Jin Hyeok Kim, Yang WangAbstract:Abstract Coagulation of humic acid–kaolin Synthetic Water was conducted with Titanium tetrachloride (TiCl4) and/or polydimethyldiallylammonium chloride (PD) to assess the effect of coagulant aid PD on coagulation behavior and floc characteristics. Coagulation behavior was investigated in terms of the reduction of turbidity and the removal of natural organic matter (NOM). The results show that the humic acid (HA) removal increased with the addition of PD depending on the doses of it and TiCl4, and the HA removal was more enhanced by PD at low TiCl4 doses than at higher ones. In addition, PD–TiCl4 (PD dosed firstly, followed by TiCl4 addition) gave better turbidity and HA removal than TiCl4–PD (TiCl4 dosed firstly, followed by PD addition) in this investigation. The growth, breakage, regrowth and fractal nature of flocs was investigated by use of Mastersizer 2000. TiCl4 plus cationic polymer PD exhibited an apparent improvement on floc size and floc grow rate, and they were both in the following order: PD–TiCl4 > TiCl4–PD > TiCl4. Compared with TiCl4, the dual-coagulants significantly improved the floc recoverability. Besides, the dual-coagulants gave more compact floc structure than TiCl4 coagulant at each coagulant dose under investigation and the values of fractal dimension (Df) were in the order of TiCl4–PD > PD–TiCl4 > TiCl4.
Qinyan Yue - One of the best experts on this subject based on the ideXlab platform.
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the disinfection by products precursors removal efficiency and the subsequent effects on chlorine decay for humic acid Synthetic Water treated by coagulation process and coagulation ultrafiltration process
Chemical Engineering Journal, 2012Co-Authors: Yan Wang, Qinyan Yue, Baoyu Gao, Qian Wang, Yanxia ZhaoAbstract:Abstract The disinfection by-products (DBPs) precursors removal efficiency and the subsequent effects on chlorine decay of coagulation–ultrafiltration process were studied in a laboratory in comparison with coagulation process. And the relation between flocs properties and the performance of coagulation–ultrafiltration process was investigated by the experiments of flocs size, fractal dimension and the surface charge. The removal efficiency of coagulation–ultrafiltration process showed that turbidity and UV254 could be removed efficiently regardless of polyferric chloride (PFC) dosage and solution pH. Even when dosage was 3 mg L−1, the turbidity and UV254 removal efficiencies were higher than 90% in coagulation–ultrafiltration process. The chlorine decay showed that under various technological conditions, the difference between chlorine decay curves obtained by coagulation–ultrafiltration process was less than that obtained by coagulation process. According to the analysis by AQUASIM software, the concentration of fast reducing agents (FRA) in coagulation–ultrafiltration process is lower than that in coagulation process, but the concentration of Slow Reducing Agents (SRA) in coagulation–ultrafiltration process was higher than in coagulation process except dosage = 18 mg L−1. Comparing the flocs properties to the performance of coagulation–ultrafiltration process, it can be found that when flocs size was small ( 200 μm), the HA removal efficiency was influenced mainly by flocs structure. The more compact the flocs, the higher the HA removal efficiency.
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synthesis and floc properties of polymeric ferric aluminum chloride polydimethyl diallylammonium chloride coagulant in coagulating humic acid kaolin Synthetic Water
Chemical Engineering Journal, 2012Co-Authors: Baoyu Gao, Qinyan Yue, Cuizhen Sun, Baichuan Cao, Zhibin ZhangAbstract:Abstract In this paper, new composite coagulants, polymeric ferric aluminum–polydimethyl diallylammonium chloride, were synthesized by combing inorganic coagulant polymeric ferric aluminum chloride (PFAC) with organic coagulant polymer polydimethyl diallylammonium chloride (PDMDAAC) under different molecular weight ratio (ferrum and aluminum to PDMDAAC, Wr = 20, 10 and 4) and the same basicity. Furthermore, flocculating mechanisms and performance of these new composite coagulants were investigated in treating humic–kaolin Synthetic wasteWater. The growth, breakage, and regrowth of flocs during coagulation using composite coagulants were measured under optimal dosage and neutral conditions by a laser diffraction instrument. The coagulation results indicated that the new composite coagulants exhibited better coagulation performance than PFAC for removing turbidity and dissolved organic matter. For the composite coagulants, the predominant coagulation mechanisms were bridge formation and charge neutralisation. The composite coagulants with different molecular weight ratio gave different steady-state floc size, strength and reflocculation ability. Both the floc size and reflocculation ability were in the same order of Wr = 4 > Wr = 10 > Wr = 20 > PFAC, while the order of floc strength was in the order of Wr = 20 > Wr = 10 > Wr = 4 > PFAC.
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the impacts of coagulant aid polydimethyldiallylammonium chloride on coagulation performances and floc characteristics in humic acid kaolin Synthetic Water treatment with titanium tetrachloride
Chemical Engineering Journal, 2011Co-Authors: Yanxia Zhao, Ho Kyong Shon, Baoyu Gao, Qinyan Yue, Hongyan Rong, Jin Hyeok Kim, Yang WangAbstract:Abstract Coagulation of humic acid–kaolin Synthetic Water was conducted with Titanium tetrachloride (TiCl4) and/or polydimethyldiallylammonium chloride (PD) to assess the effect of coagulant aid PD on coagulation behavior and floc characteristics. Coagulation behavior was investigated in terms of the reduction of turbidity and the removal of natural organic matter (NOM). The results show that the humic acid (HA) removal increased with the addition of PD depending on the doses of it and TiCl4, and the HA removal was more enhanced by PD at low TiCl4 doses than at higher ones. In addition, PD–TiCl4 (PD dosed firstly, followed by TiCl4 addition) gave better turbidity and HA removal than TiCl4–PD (TiCl4 dosed firstly, followed by PD addition) in this investigation. The growth, breakage, regrowth and fractal nature of flocs was investigated by use of Mastersizer 2000. TiCl4 plus cationic polymer PD exhibited an apparent improvement on floc size and floc grow rate, and they were both in the following order: PD–TiCl4 > TiCl4–PD > TiCl4. Compared with TiCl4, the dual-coagulants significantly improved the floc recoverability. Besides, the dual-coagulants gave more compact floc structure than TiCl4 coagulant at each coagulant dose under investigation and the values of fractal dimension (Df) were in the order of TiCl4–PD > PD–TiCl4 > TiCl4.
